From 169e9cbd77db23fe50bc8ba68bf081adb67b4220 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Fri, 1 Jun 2012 16:52:37 +0200 Subject: x86, cpu, amd: Fix crash as Xen Dom0 on AMD Trinity systems f7f286a910221 ("x86/amd: Re-enable CPU topology extensions in case BIOS has disabled it") wrongfully added code which used the AMD-specific {rd,wr}msr variants for no real reason. This caused boot panics on xen which wasn't initializing the {rd,wr}msr_safe_regs pv_ops members properly. This, in turn, caused a heated discussion leading to us reviewing all uses of the AMD-specific variants and removing them where unneeded (almost everywhere except an obscure K8 BIOS fix, see 6b0f43ddfa358). Finally, this patch switches to the standard {rd,wr}msr*_safe* variants which should've been used in the first place anyway and avoided unneeded excitation with xen. Signed-off-by: Andre Przywara Link: http://lkml.kernel.org/r/1338562358-28182-4-git-send-email-bp@amd64.org Cc: Andreas Herrmann Link: [Boris: correct and expand commit message] Signed-off-by: Borislav Petkov Acked-by: Konrad Rzeszutek Wilk Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/amd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/cpu/amd.c') diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 146bb6218eec..80ccd99542e6 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -586,9 +586,9 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) !cpu_has(c, X86_FEATURE_TOPOEXT)) { u64 val; - if (!rdmsrl_amd_safe(0xc0011005, &val)) { + if (!rdmsrl_safe(0xc0011005, &val)) { val |= 1ULL << 54; - wrmsrl_amd_safe(0xc0011005, val); + checking_wrmsrl(0xc0011005, val); rdmsrl(0xc0011005, val); if (val & (1ULL << 54)) { set_cpu_cap(c, X86_FEATURE_TOPOEXT); -- cgit v1.2.3 From 2c929ce6f1ed1302be225512b433e6a6554f71a4 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Fri, 1 Jun 2012 16:52:38 +0200 Subject: x86, cpu, amd: Deprecate AMD-specific MSR variants Now that all users of {rd,wr}msr_amd_safe have been fixed, deprecate its use by making them private to amd.c and adding warnings when used on anything else beside K8. Signed-off-by: Borislav Petkov Link: http://lkml.kernel.org/r/1338562358-28182-5-git-send-email-bp@amd64.org Acked-by: Konrad Rzeszutek Wilk Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/amd.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'arch/x86/kernel/cpu/amd.c') diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 80ccd99542e6..c928eb26ada6 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -19,6 +19,39 @@ #include "cpu.h" +static inline int rdmsrl_amd_safe(unsigned msr, unsigned long long *p) +{ + struct cpuinfo_x86 *c = &cpu_data(smp_processor_id()); + u32 gprs[8] = { 0 }; + int err; + + WARN_ONCE((c->x86 != 0xf), "%s should only be used on K8!\n", __func__); + + gprs[1] = msr; + gprs[7] = 0x9c5a203a; + + err = rdmsr_safe_regs(gprs); + + *p = gprs[0] | ((u64)gprs[2] << 32); + + return err; +} + +static inline int wrmsrl_amd_safe(unsigned msr, unsigned long long val) +{ + struct cpuinfo_x86 *c = &cpu_data(smp_processor_id()); + u32 gprs[8] = { 0 }; + + WARN_ONCE((c->x86 != 0xf), "%s should only be used on K8!\n", __func__); + + gprs[0] = (u32)val; + gprs[1] = msr; + gprs[2] = val >> 32; + gprs[7] = 0x9c5a203a; + + return wrmsr_safe_regs(gprs); +} + #ifdef CONFIG_X86_32 /* * B step AMD K6 before B 9730xxxx have hardware bugs that can cause -- cgit v1.2.3 From 715c85b1fc824e9cd0ea07d6ceb80d2262f32e90 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Thu, 7 Jun 2012 13:32:04 -0700 Subject: x86, cpu: Rename checking_wrmsrl() to wrmsrl_safe() Rename checking_wrmsrl() to wrmsrl_safe(), to match the naming convention used by all the other MSR access functions/macros. Signed-off-by: H. Peter Anvin --- arch/x86/kernel/cpu/amd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/cpu/amd.c') diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index c928eb26ada6..9d92e19039f0 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -621,7 +621,7 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) if (!rdmsrl_safe(0xc0011005, &val)) { val |= 1ULL << 54; - checking_wrmsrl(0xc0011005, val); + wrmsrl_safe(0xc0011005, val); rdmsrl(0xc0011005, val); if (val & (1ULL << 54)) { set_cpu_cap(c, X86_FEATURE_TOPOEXT); @@ -712,7 +712,7 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) err = rdmsrl_safe(MSR_AMD64_MCx_MASK(4), &mask); if (err == 0) { mask |= (1 << 10); - checking_wrmsrl(MSR_AMD64_MCx_MASK(4), mask); + wrmsrl_safe(MSR_AMD64_MCx_MASK(4), mask); } } -- cgit v1.2.3